Steel process.



J. OHURGHWARD.

STEEL PROCESS.

APPLICATION FILED 111111. 18, 1911.

1 ,069,387, v Patented Aug. 5, 1913.

INVENTOR 4 TTORNEYS UNITED STATES PATENT curios.

JAMES CHUBGHWARD, OF MbUNT VERNON, NEW YORK, ASSIGNOR TO CHUBCHWARDINTERNATIONAL STEEL COM-.PAKY, OF NEW YORK, N. Y., A CORPORATION 01?DELA- WARE.

STEEL PROCESS.

Specification of Letters Patent.

Application filed March 18, 1911.

Serial No. 615,305.

specific features, to a means for producing a fibrous structure in steeland compositions of steel.

One of the objects of the invention is to provide a practical andeficient process of the kind described for removing from the substancetreated that property which induces its granular form.

Another object is to provide a process of the 'kind described wherebythe physical and chemical characteristics of the resulting product maybe easily controlled.

Another object is to provide a rapid process of the kinddescribed whichwill be simple and inexpensive.

Another object is to produce a steel product which-shall be cheap and atthe sametime possess high physical constants and,

in general, desirable chemical and physical properties.

Other objects will be in part obvious and in part pointed outhereinafter. v

The invention accordingly consists in the several steps and the relationand order of one or more of said.- steps with relation to each of theothers thereof which will be exemplifiedv in the hereinafter disclosedprocess and the scope of. the application; of which will be indicated inthecjlaims that follow.

The drawing represents a specimen of 4a the material made in accordancewith the invention.

In order to render certain aspects of the invention clearer, it is to benoted that steel and compositions of steel ordinarily possess a granularcrystalline structure.- Further, in the process of steel. formation theparticles making up the bod of the material seem to assume a globu arform or to globulize, and. in consequence thereof the efiect oi certainvaluable characteristics in the completed product'is diminished. Experinent indicatesthat the granular structure 1s due, at least in part, to acertain Patented Aug. 5, 1913.

astringent capacity of the carbon, appearing in substantially allvsteels and composi tions of iron and carbon. By virtue of this capacity,when carbon is brought into contact with molten iron fibers in a furnaceor metal bat-h, it exercises a contracting action thereupon and drawsthe fibers into globules. When steel is formed in the usual way thisastringent capacity of carbon acts as indicated and upon casting andcooling, a granular crystalline structure results.

It has been found, in accordance with the present invention, that thisastringent ca pacity of carbon 1 may be removed from steels of all typesby heating them to a temperature of approximately 3100 F. andmaintaining themat that temperature for acertain interval. The metalupon cooling will be found to have assumed a fibrous form.

According to the length of time during which the substances aresubjected to the process and to the temperature employed in carrying itout, the characteristics of the product will be altered. At atemperature of approximately 3150 F. the action will begin to take placein from fifteen to twenty minutes. Its completeness may be judged by a,practised eye by observing the manner in which the bath boils. Thetemperature must be maintained at this point for another ten to fifteenminutes to allow the globules to assume a fibrous form. If the lowesttemperature at which the reaction takes place is used and too short atime is allowed for reforming, the finished product shows by itscrystals only the commencement of fiber formation. On the other hand,with the use of an excessive temperature, say above 3250 F. for too longa time, practically all of the carbon will be removed or technicallyboiled out from the metal. This boiling out of the carbon will alsotakeplace if a comparatively low temperature, say, slightly above 3100F. is employed for too long a time. r

The length of time during which the combination of iron and carbon mustbe sub' jectedto the process also varies somewhat according to the kindof carbonaceous macarbons.

For example, vegetable carbons, or carbons extracted and obtained fromvegetable matter, provide the quickest and most violent reaction. Bonecarbons are next in order of rapidity and then in succession in thescale of rapidity, mineral carbons and crustacean The difierence in timein the case of the most rapid and least rapid carbons in the scale ishowever, short, being not more than five minutes between vegetable andcrustacean carbon. It is tobe noted that the character of the carbonalso leaves its impression on the physical qualities of the steel; thus,one per cent. of vegetable carbon in a steel product gives a very muchmore ductile product than if one per cent. of crustacean carbon is used,and there is also a marked degree of diflerence in the hardness of thetwo metals.

The following tabulation is an example of the composition of a steelmade according to the process If a temperature of 3150 F. to 3200 F. isused and the proper time is allowed to remove the granular structure ofthe materials, the product obtained will have a wholly fibrousconsistency and may be split like a piece of hard wood.

A product may be obtained by means of this process which is hard, tough,compact and durable, and possesses an integral fibrous structureresembling that of wood, such as oak, (as shown in the drawing).Further, a product may be obtained which is generally heavier thanchemically similar compositions of steel having a granular structure.The relatively heavy character of the product as compared with ordinarysteel is probably due to its greater compactness, two specimens whichwere tested showing Ia greater specific gravity than ordinary stee Afterthe fibrous structure has been given to the steel or steel composition,in case it is desired to work the resulting product into various shapesand forms, it may be passed through the customary casting, welding andforging processes. The heating which is usually necessary in theseprocesses is apt to alter the structural relations of the fibers, butthese may be readily restored by reheating the material after it hasbeen worked into any desired form to a predetermined temperature,maintaining it at this temperature until'the fibers have resumed theiroriginal positions, and subsequently roeasav cooling it. The temperatureemployed in reheating will vary according to the kind of metal undertreatment and also according to the intended use of the metal. Forexample, the steel mentioned above might be reheated to approximately1605 to 1650 F., maintained there for a time, and then cooled. It may befound advisable in some instances to repeat, at successively lowertemperatures, this reheating and cooling, and if this is done a morecompact product is assured in view of the fact that thereby themolecules are expanded and enlarged to fill the pores of the structure.For example, the steel mentioned might be reheated again toapproximately 1290 to 1335 F. and cooled, then once more reheated toapproximately 1070 to 1110 F. and cooled. It is preferable, inconducting the heating processes, to maintain the metal at the desiredtempera ture until it has acquired an even heat throughout.

The process is applicable to alloy or special steels, if the precautionsfor restoring the alloys to the original chemical union of each, afterheating to the high temperature necessary for this process, is observed,as set forth in my U. S. Letters Patent Numbers 855,756, 883,698,884,009 and 899,713. For example, if the steel is alloyed with manganesethe temperatures which will be used for restoring the chemical union ofthe alloy and preserving the fibrous structure will be as follows:First: From approximately 1600 F. to approxi- 100 mately 1650 F. Second:From approximately 1290 F. to approximately 1340 F. for the restorationand redistribution of the carbon. Third: From approximately 1025 F. toapproximately 1110 F. in case the 105 metal must be extraordinarilytough. After each of these restoring heating processes the metal may bequenched, preferably in oil, or it may be slowly cooled. Slow coolingwill give the greatest toughness.

It will thus be seen that a simple, practical process is providedwherein the objects of the invention are achieved.

., The product formed according to the present process shows highphysical con- 115 stants, for instance, great tensile strength,ductility, etc. It also possesses all of the desirable physical andchemical properties of ordinary steel. There is a tendency in somesteels made by ordinary processes to 12.0 rust, due to the presence ofcertain constituents added to improve the physical constants and otherqualities of the steel, but

the article made by the present process shows great resistance to rustand withal is a 125 highly desirable and durable product.

As many changes could be made in carrying out the above process withouteparting from the scope of the invention, it is intended that all mattercontained in the above 130 description shall be interpreted asillustrative and not in a limiting sense. It is also to be understoodthat the language used in the following claims is intended to cover allof the generic and specific features of the invention herein describedand all statements of the scope of the invention, which, as a matter oflanguage, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secureby Letters Patent is i 1. A process of the nature disclosed, whichconsists in subjecting a combination ofc'arbon and iron to an agentadapted to remove the astringent capacity of the carbon, where by theresulting combination of iron and carbon assumes a fibrous structure.

2. A process of the nature disclosed, which consists in heating acombination of carbon 9 and iron, having a granular structure, wherebythe astringent capacity residing in the combination is removed and thestruct-ure of the resulting'product is rendered fibrous.

3. A process of the naturedisclosed, which 1 consists in heating acombination of carbon .and iron having a granular structure toapproximately 3100 F. and maintaining said temperature whereby saidcombination assumes a fibrous structure upon solidifying.

4. A process of the nature disclosed, which consists in heating steelhaving a granular structure to approximately 3100 F. and maintainingsaid temperature for a predetermined interval f whereby the granularstructure of said steel is changed and upon solidifying it assumes afibrous structure.

5. A process of the nature discloserhwhich consists in subjecting acombination of carlion and iron'having agranular structure to an agentadapted to destroy said granular structure whereby said'combinationassumes a fibrous structure, working said'combination of carbon and ironinto an object of any desired form and maintaining said object at apredetermined temperature to restructure due to the working of saidsteel is rectified and the fibers a're swelled to form a compact andcontinuous surface.

7. As an article of manufacture, a com position, containing iron andcarbon having an integral fibrous structure resembling that of hard woodand possessing generally.

greater weight than chemically similar compositions of iron andcarbonhaving other than a fibrous structure, substantially asdefscribed. 1

8, A process of the nature disclosed, which consists in heating acombination of iron and carbon havinga granular structure to atemperature which will remove the astringent quality of the carbon, andthen maintaining the temperature for a sufiicient time l and such as tochange the molecular structure of the combination to .fibrous uponsolidifying.

In testimony whereof I afiix' my signature, in the presence of twowitnesses.

JAMES CHURCHWARD. Witnesses: JQTHOMSQN,

. L. A. WATSON.

